Besides solid, liquid and gaseous, plasma is the fourth state of aggregation of matter. It can be used, in the form of a low-temperature plasma, as at least partially ionized gas, for numerous applications for treating surfaces. Thus, surface activation is conceivable, but so too is surface cleaning, owing to the disinfecting/sterilizing action of low-temperature plasma.
DE 10 2006 019 664 A1 describes a cold-plasma handheld device for plasma treatment of surfaces. A high-voltage unit, having an adaptation network for generating the high voltage required for producing plasma, is built into a handle, or handheld casing. A process gas is routed through the high-voltage unit. The plasma jet that is produced after passage through the high-voltage generator is driven outward by the gas stream, and emerges in a relatively highly focused manner. In order to widen the plasma stream, the plasma nozzle can be widened and provided with a slot.
DE 10 2009 028 190 A1 discloses a plasma handheld device having an integrated high-frequency generator, and having a gas inlet for supplying process gas. Again, a plasma jet, driven by the process gas, emerges from a nozzle at the outside-face end of the plasma handheld device. Since the plasma nozzle, the high-voltage source and a high-frequency generator are integrated into the easily handled plasma tool, the spurious electromagnetic radiation is reduced. For differing plasma beams, various types of electrode may be provided, such as needle-shaped electrodes, blade-shaped electrodes, or a plurality of needle-shaped electrodes arranged next to each other.
DE 10 2009 047 220 A1 describes an appliance and a method for generating a pulsed, cold atmospheric-pressure plasma for antimicrobial plasma treatment (sanitization, disinfection, sterilization, decontamination) of extremely small surfaces and cavities, with pinpoint precision. A process gas is introduced into a handheld device via a gas inlet, and routed through a high-voltage electrode for the purpose of ionization. The electrically conductive object to be treated serves as a counter-electrode. In order to enlarge the receiving plane, a parallel circuit of a plurality of electrodes can be provided for the purpose of upscaling.
CN 101778525 A describes a pneumatically rotatable air plasma jet source, in which a plasma jet flows out of a rotatable, obliquely oriented nozzle.